PlayStations (especially PS5) do not use standard HTTP GET requests on port 80 to detect captive portals and as far as I remember, Meraki’s splash page redirection only works with HTTP traffic on port 80.
I am not a Cisco Meraki employee. My suggestions are based on documentation of Meraki best practices and day-to-day experience.
Please, if this post was useful, leave your kudos and mark it as solved.